There are a method of using a transmitted light, a method of using a reflected light and so on, as a method of taking an image of a biological body in a biometric authentication. In a case where an image of a biological body under a skin such as a vein is taken, a diffusion light that is included in a reflected light, diffuses inside of a palm and returns is used. In this case, a surface reflection light reflecting at the skin is a noise. Therefore, when the surface reflection light and the diffusion light are superpositioned with each other, detecting of a biological body is difficult.
The following technologies are known as a method of taking an image without the surface reflection. In Japanese Patent Application Publication No. 2002-200050 (hereinafter referred to as Document 1), surface reflection is removed with use of a polarization filter. In Japanese Patent Application Publication No. 2002-514098 (hereinafter referred to as Document 2), a surface reflection component is removed by controlling “on” and “off” of a plurality of light sources.